How To Add a Subscribe Option to your Facebook Profile

Facebook has added an option to let people "subscribe" to your profile just like the way they follow you on Twitter. Whenever you post an update on your wall with the privacy option set as “Public”, it will appear in the "News Feed" section of your subscribers.
The Subscribe button that sits on the top right side of a profile and wall page lets you hear from interesting people you're not friends with—like journalists, artists and political figures. Subscribers can choose what type of updates they want to see in their News Feeds. This includes: All updates, Most updates and Important Updates. There are further options to select the types of updates that should be posted to a News Feed. These can be live events, status updates, games, photos and videos. To add the subscribe button to Facebook and start getting subscribers, go to the Subscriptions tab on the left-hand side of your profile. Or, visit this subscription page and click Allow Subscribers. There on you can select whether you want subscribers to comment on your updates or get notified about new subscribers. You're done!
However "Subscribe" is an opt-in feature. The only people who allow subscribers will have a Subscribe button on their profile. If you don't see the button, you can't subscribe.